1. Field of the Invention
The present invention relates to an image forming device, and more particularly, to an image forming device to distinguish between types of a printing medium and a driving control method thereof.
2. Description of the Related Art
Generally, an image forming device such as a printer or a multi-function device can select a printing medium in accordance with a type of an image to be printed and can use various printing methods corresponding to characteristics of the selected printing medium. An image forming device such as a color ink-jet printer, which can output a multicolor image such as a photo, by using ink, selects either general paper or coating paper coated with some material to prevent the ink from being smudged. This selection is made in accordance with the type of the image to be printed. The image forming device then outputs the image in a printing method corresponding to the selected paper, thereby improving the printing quality of the output image. A user is required to separately manipulate the image forming device through a terminal connected to the image forming device or an image forming device body.
A disadvantage of the conventional image forming device is that a user must pre-set the type of the printing paper by manipulating the terminal or the image forming device body each time an image is printed. In order to overcome this disadvantage, an image forming device having a paper type distinguishing sensor, which is provided at an image forming portion or a paper feeding apparatus, has been developed. The paper type distinguishing sensor distinguishes the type of the printing paper. Then, the sensor outputs a paper distinguishing signal to a controller of the image forming device or a controller of a terminal to select a printing method according to the distinguished type of the printing paper.
FIG. 1 is a view showing an ink-jet printer 100 having a paper type distinguishing sensor 190 disposed adjacent to a printing nozzle 115 functioning as an image forming portion. As shown in FIG. 1, the paper type distinguishing sensor 190 is disposed between the printing nozzle 115 and a feeding roller 131, and also at a bottom of a printer head 110, to distinguish the type of printing paper 10 before an image is printed on the printing paper 10 by the printing nozzle 115.
The operation of the ink-jet printer 100 of FIG. 1 will now be described. First, a pickup roller 135 is operated to convey the printing paper 10 from a paper feeding apparatus 120 to a paper conveyance path 140. The printing paper 10 conveyed to the paper conveyance path 140 is moved toward the feeding roller 131 by a drive roller 133. The feeding roller 131, the drive roller 133, and the pickup roller 135 are part of a paper conveyance apparatus 130. The paper conveyance path 140 is formed by guide members 160a, 160b and 160c. The printing paper 10 enters into the feeding roller 131, which is detected by a detection unit including a paper entrance detection member 150, which pivots in a rotation shaft 151, and is disposed between the feeding roller 131 and the drive roller 133. When the detection unit outputs a detection signal, the feeding roller 131 is rotated in a reverse direction (opposite to arrow ‘a’) for a predetermined time. As a result, a front end of the printing paper 10 is aligned to be parallel to the feeding roller 131. Then, the feeding roller 131 is rotated in a normal direction (a) until the printing paper 10 arrives at the paper type distinguishing sensor 190. Then, the feeding roller 131 is stopped. At this point, the paper type distinguishing sensor 190 distinguishes the type of the printing paper 10. Next, the feeding roller 131 is re-rotated in the normal direction (a) to convey the printing paper 10 to a lower portion of the printing nozzle 115. Then, the printing nozzle 115 prints an image on the printing paper 10 corresponding to an input data signal, completing a printing cycle.
In the ink-jet printer 100, however, the feeding roller 131 must be reverse-rotated for the alignment of the front end of the printing paper 10 prior to conveying the printing paper 10 to the printing nozzle 115, and after a predetermined time, the feeding roller 131 is rotated in the normal direction (a) to convey the printing paper 10 to the printing nozzle 115. Before the printing paper 10 arrives at the printing nozzle 115, the feeding roller 131 is stopped for the paper type distinguishing sensor 190 to distinguish the type of the printing paper 10, and then is re-rotated in the normal direction (a). Therefore, there is a problem of decreasing a printing speed of the ink jet printer 100.
In particular, when a paper margin is required to be narrow due to a large image to be printed, the feeding roller 131 is reverse-rotated to retrieve the printing paper 10 from a lower portion of the printer head 110 after distinguishing of the type of the printing paper 10. Then, the feeding roller 131 re-enters the printing paper 10 to the printing nozzle 115 when the printing nozzle 115 is ready to print. Thus, the printing speed of the ink jet printer 100 is further decreased.